The University of Florida
Ongoing study at the University of Florida
The seizures exhibited by foals with JIE are generally classic tonic-clonic seizures (Aleman et al, 2006). A tonic-clonic seizure begins with muscle stiffness all over the body and the foal might fall over. After the muscles cease the stiffening the clonic phase begins with rapid muscle contractions all over the body. The seizures can last from only a few seconds up to about 5 minutes (Aleman et al, 2006). During this time the horse may lose consciousness, and could possibly injure itself while either falling over or thrashing on the ground. Once the episode has ended the foal usually exhibits some postictal (post-seizure) signs including blindness, lethargic behavior, and disorientation (Aleman et al, 2006). Once the horse has outgrown the seizures it can usually go on to live a normal healthy life.
Epilepsy refers to a diverse group of chronic disorders where the individual has recurrent seizures without precipitating factors (Aleman et al, 2006). When a foal exhibits Juvenile Epilepsy it usually presents signs between 2 days and 6 months of age (Aleman et al, 2006). An affected foal might display blindness, lethargic behavior, and a decrease or complete lack of the menace response; however, foals do not always display the same signs and may only exhibit one or two of the aforementioned (Aleman et al, 2006). The seizures usually happen in clusters over a three day period where the foal might exhibit these signs, in addition to not nursing or eating, and depression (Aleman et al, 2006).
Juvenile Idiopathic Epilepsy (JIE) is a disease first reported in Arabian horses of a young age. JIE is thought to be a genetic disorder, but as of now no extensive work has been done to identify the exact genetic mode of inheritance.
Please contact the Brooks Equine Genetics Lab for more information. You can reach us by phone at (352) 273-8080 or email, firstname.lastname@example.org.
While JIE is usually outgrown by the time the foal is between 12 and 18 months old, and the disease is generally not fatal, any time the horse has a seizure there is a danger of injury and possible death. Anti-seizure medications have been effective in reducing frequency and severity of the seizures and are helpful in decreasing risk of injury during an episode (Aleman et al, 2006).
1. Aleman, M., Gray, L., Williams, D., Holliday, T., Madigan, J., LeCouteur, R. and Magdesian, K. (2006). Juvenile idiopathic epilepsy in Egyptian Arabian foals: 22 cases (1985-2005). Journal of Internal Veterinary Medicine, [online] 6, pp.1443-9. Available at: http://www.ncbi.nlm.nih.gov/pubmed/17186863 [Accessed 3 Nov. 2014]. 2. Biervert, C. (1998). A Potassium Channel Mutation in Neonatal Human Epilepsy. Science, 279(5349), pp.403-406. 3. Lichter-Peled, A., Polani, S., Stanyon, R., Rocchi, M. and Kahila Bar-Gal, G. (2013). Role of KCNQ2 and KCNQ3 genes in juvenile idiopathic epilepsy in Arabian foals. The Veterinary Journal, 196(1), pp.57-63. Image 1. "Scarlettheta" by Ealdgyth - Own work. Licensed under Creative Commons Attribution-Share Alike 3.0-2.5-2.0-1.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Scarlettheta.jpg#mediaviewer/File:Scarlettheta.jpg
We need DNA samples from horses who have been previously diagnosed with JIE, as well as horses who have had an offspring with JIE. All studies are confidential, so be assured both you and your horse’s identity will not be released at any point should you decide to participate.